Practical cardiology for surgeons and anesthetists Yong-Wei Joey Hung, BVM, MS Taiwan Academy of Veterinary Internal Medicine Cardiospecial Veterinary Hospital Introduction WHAT S THE DIFFERENCE? Routine anesthesia protocol for normal animals may cause severe decompensation in heart diseased patients General Principles Hemodynamic change Interaction between cardiac and anesthetic drugs Pre-existing arrhythmia Anesthetic drugs predispose to arrhythmia Length of anesthesia and analgesia All anesthetic drugs directly depress cardiac function, alter vascular tone, or modify normal CV regulatory mechanism Etiology of the cardiac disease Cardiovascular physiology 1. Ca ion binds to troponin 2. Tropomyosin aside and actin binding site for myosin exposed. 3. ADP and P are attached to myosin head 4. Myosin head attach to actin binding site to form cross bridge and P released. 5. Myosin head move so actin myofilament past myosin filament. ADP is released. 6. ATP binds to myosin head to break the bond. ATP is borken into ADP and P, releasing energy and store in myosin head for next movement. Diagnose the etiology of heart disease Left to right shunt: causing pulmonary hyperperfusion. 1
Diagnose the etiology of heart disease Right to left shunt: causing pulmonary hypoperfusion. Diagnose the etiology of heart disease Heart failure: Forward failure, cold Backward failure, wet Functional classification of heart failure Asymptomatic- no stabilization needed Mild to moderate heart failure- 1. stabilization and the lack of clinical signs for several days with drugs prior to sedation or anesthesia 2. for emergency surgery, parenteral cardiac drugs to control clinical signs as possible. Continue and aggressive monitoring b4, during and after surgery. Advanced heart failure- cardiogenic shock or death may occur Anesthetic Risk Classification ASA five categories based on physical status Most clinically stable cardiac patients are ASA II or III ASA IV should not be anesthetized b4 stabilization ASA V- stabilization may not be possible and death is likely History Systemic, metabolic, or cardiovascular compromises? the stage of heart failure? the rate of disease progression? hacking cough, exercise intolerance, dyspnea, weight loss, ascites, syncope, current drug therapies and their responses. Preanesthetic diagnostic evaluation and lab tests Complete diagnostic cardiac evaluation: PE, Chest Rads, ECG, ECHO. Physical exam: auscultation of heart and lungs; Character of peripheral pulse, jugular veins, mucus membrane, and CRT; detection of pulse deficit Physical exam and ECG CBC and biochem esp. renal and electrolyte parameters 2
Preanesthetic diagnostic evaluation and lab tests Indications of poor systemic output: Pallor Prolonged CRT Mental depression Abnormal jugular venous pulses Abnormal femoral pulses Indications of stenotic or insufficient cardiac valve: cardiac murmur Preanesthetic diagnostic evaluation and lab tests Indication of arrhythmia: pulse deficit Abnormal auscultation Indication of respiratory disease or pulmonary edema: abnormal lung sound Indication of abnormal fluid accumulation: percuss pleural effusion, percuss ascites, crackles Cardiac drugs and potential anesthetic drugs interaction Diuretics Furosemide - hypokalemia-1.tachycardia 2. predipose to digoxin toxicity - dehydration- predispose to hypotension during anesthesia or sedation Spironolactone - hyperkalemia- tachycardia; bradycardia; arrhythmia Thiazide diuretics - hypokalemia; hypomagnesemia- tachycardia Cardiac drugs and potential anesthetic drugs interaction ACEI Arterial vasodilation - arterial hypotension. acepromazine, isoflurane, and sevoflurane Cardiac drugs and potential anesthetic drugs interaction Digoxin sympathomimetics Hypokalemia. Hyperventilation(hypocarbia and concurrent resp. alkalosis). Blood digitalis level prior to anesthesia Cardiac drugs and potential anesthetic drugs interaction Vasodilators-hydralazine Reflex tachycardia and water retention Worsen the tachycardia caused by sympathomimetics. Fluid therapy must be minimized and monitored closely. Acepromazine, isoflurane and sevoflurane. 3
Cardiac drugs and potential anesthetic drugs interaction Calcium Channel Blocker Vasodilation, bradycardia, and decreased contractility. Acepromazine, isoflurane or sevoflurane Opioids and inhalation anesthetics. Propofol Cardiac drugs and potential anesthetic drugs interaction Beta-adrenergic blocker Bradycardia and decreased contractility Opioids and inhalation anesthetics Sympathomimetics Propofol Cardiac drugs and potential anesthetic drugs interaction Class I antiarrhythmic agents Tocainamide or Procainamide Propofol Cardiac drugs and potential anesthetic drugs interaction Anti-thrombotic agents Aspirin and clopidogrel Acepromazine Cardiac drugs and potential anesthetic drugs interaction Combination Drug Therapy Potential side effects of each drug Potential side effects of the combination of drugs Inhalation anesthetics or not? Anesthetic drug selection and supportive care O2 and ventilatory support O2 by mask at >5L/min Intubated patients 100% O2 Ventilatory support-4 to 6 breaths/min. Isoflurane and sevoflurane - hypoxemia or hypercarbia - arrhythmia. 4
Anesthetics that are contraindicated in cardiac patients alpha-2 adrenergic drugs Xylazine Medetomidine Dexmedetomidine Anesthetics that are contraindicated in cardiac patients inhalation agents Halothane VERY potent negative inotropic effect Halothane arrhythmia Methoxyflurane less negative inotropic than halothane but very long recovery and should not be used Mask induction not recommended. Isoflurane pungent odor - laryngospasm esp. in cats Anesthetics that are contraindicated in cardiac patients barbiturates Thiopental Anesthetic drugs that should be used with caution Tranquilizers- Acepromazine peripheral vasodilation minimal effects on contractility and resp. Hypotension - IV fluid, and peripheral vasoconstriction agents. Acepromazine with very low dosage Anesthetic drugs that should be used with caution Anticholinergics- Not recommended unless bradyarrhythmia, excessive upper airway secretions, or bronchoconstriction or in which Q depends on high resting HR. Tachycardia (VT, or SVT), increased myocardial O2 consumption, focal ischemi,a and arrhythmias. Glycopyrrolate longer duration than atropine Anesthetic drugs that should be used with caution IV induction agents Thiopental may sensitize the heart to catecholamine. Propofol similar side effect to thiopental but less potent. Fast injection may lead to profound apnea. 5
Anesthetic drugs that should be used with caution IV induction agents Dissociatives- Ketamine and Zolatil not recommended in pre-existing arrhythmia Ketamine or Zolatil should not be the sole anesthetic agent in HCM cats Reduce pre-op anxiety and stress, Provide preemptive analgesia, Lower the requirement of IV induction and inhalation agents, Ensure a smooth recovery. Benzodiazepines Diazepam and midazolam, minor tranquilizers, not profound sedation. In advanced age or diseases, could produce profound effect Antiarrhythmic effects With opioids to produce neuroleptanalgesia. Diazepam more painful when IM. (propylene glycol base) Antagonist: flumazenil Opioids-analgesia Do not greatly affect contractility and vascular tone Antagonist naloxone Opioids morphine Minimal sedation in healthy but profound sedation in compromised patients Vomiting and bradycardia. Bradycardia is anticholinergic responsive Morphine - histamine release - peripheral vasodilation. Dose dependant. Resp depression is dose dependent Opioid agonist hydromorphone and oxymorphone 10 times more potent analgesia More sedative than morphine May slow HR by parasymp mech Less resp effect than morphine Less likely to produce vomiting than morphine 6
Opioid agonist fentanyl 100 times analgesic than morphine Rapid action, short duration - CRI Bradycardia - anticholinergics Opioid agonist/antagonist butorphanol Less sedation than opioid agonist. Minimal cardiopulmonary depression Rarely bradycardia Ceiling effect Vomiting rarely occur Poor analgesia for moderate to severe pain Partial opioid agonist buprenorphine 20 times more analgesic than morphine Poor sedative Minimal cardiopulmonary depression Onset of action 20-30 min Long duration repeat injection of naloxone is required Antagonist: Naloxone, Sinus tachycardia Use only if necessary. Neuroleptanalgesics tranquilizer + opioids Cardiac patient benzodiazepine + opioids Effect within 15 min after IM Panting and resp depression in dogs( not cats) can be profound after valium/opioid agonists Bradycardia is more likely with valium/opioid agonist and respond to anticholinergics IV induction agents Barbiturate thiopental Rapid induction and recovery Cumulative effect Decrease contractility Apnea Very low dose should be safe 7
IV induction agents Dissociatives ketamine Use with diazepam or midazolam to minimize rigidity and possible seizure Combination can increase HR, maintain arterial BP Myoclonus activity and rough recovery Should not be used in HCM cats Used after neuroleptanalgesics may minimize the CV effects IV induction agents Tiletamine/zolazepam Effect similar to ketamine/diazepam when IV bolus Less myoclonus and smoother induction. Longer and potentially rougher recovery if used alone without pre-med Never use in HCM cats IV induction agents Nonbarbiturates propofol(phenolic compound) Very rapid and smooth induction and recovery Noncumulative good for CRI Decrease contractility. Use of pre-med greatly lower the required dosage for propofol and hypotension is less likely IV induction agents Nonbarbiturates - etomidate(imidazole derivative) Very fast and smooth induction/recovery Must use with pre-med. Severe myoclonus activity can occur if used alone. Minimal CP depression. Prepared with propylene glycol -> high osmolality. -> acute RBC lysis may occur. Maintenance of anesthesia Inhalation agents Isoflurane and sevoflurane Rapid induction/recovery Minimal cardiac rhythm/contractility effect Dose-dependent peripheral vasodilation -> hypotension Potent resp. depressant and can be worsen by opioids. -> ventilator support Maintenance of anesthesia Inhalation agents Nitrous oxide Rarely used due to life threatening hypoxemia 8
Injectable general anesthesia General anesthesia: sleep/muscle relaxation/analgesia Can be achieved by IV agents Injectable general anesthesia and propofol Pre-med with IM opioids/benzodiazepine Induction with propofol 1~5 mg/kg IV CRI with Propofol 0.14~0.4 mg/kg/min OR, Propofol 0.5~1 mg/kg intermittent IV Injectable general anesthesia and ketaminediazepam Pre-med with IM opioids/benzodiazepine Induction with 0.1 ml/kg of a 50:50 mixture of ketamine(100mg/ml)/diazepam(5mg/ml) 1/4 to 1/3 of the induction dose can be bolus intermittently Adjunct techniques Local anesthetic drugs Lidocaine (2%) has a rapid onset(5 min) and short duration(60 min) Can be infiltrated SQ to a max dose of 10 mg/kg in dogs and cats. Can be diluted to 1% for larger area bupivacaine(0.25%) has a longer onset(15~20 min) and duration(2~4hr) Adjunct techniques Intercostal nerve blocks Regional anesthesia for a lateral thoracotomy can be obtained by placing the local anesthetic at the dorsal most aspect of the intercostal nerves at the site of incision and 2 intercostals spaces cranial and caudal. Lidocaine: do not exceed 10 mg/kg Adjunct techniques Nondepolarizing muscle relaxant drugs(nmrds) Block effects of acetylcholine at the neuromuscular junction -> complete paralysis Use in patients with poor BP and gross purposeful movement Ventilatory support is necessary Can be reversed by neostigmine(0.02mg/kg IV) and atropine(0.02 mg/kg IV) combined in the same syringe. Occasionally, a second injection with ½ the dose is required 9
Adjunct techniques NMRDs Atracurium (0.25 mg/kg IV then 0.1 mg/kg IV PRN) Short duration(20~25 min) Does not require hepatic metabolization and renal excretion. Hypothermia and acidosis will prolong the effect of atracurium Adjunct techniques NMRDs Pancuronium (0.02~0.04 mg/kg IV then 0.01~0.02 mg/kg IV PRN) Longer duration (30-40 min) Hepatic metabolism and renal excretion is required A mild increase in HR can occur by parasympatholytic action. Monitoring and supportive care during Anesthetic depth Adequate: moderate jaw tone Deeply anesthetized: extremely loose or no jaw tone Inadequate: gross, purposeful movement Cardiopulmonary parameters HR, RR, MM color, CRT, pulse quality noninvasive monitoring ECG: always on during entire procedure post-op monitor depends on the status of the patient noninvasive monitoring ABP: indirect is less accurate than direct measurement. Trends of indirect ABP Doppler Oscillometric noninvasive monitoring Doppler ABP: Systolic, occasionally diastolic ABP can be determined Cuff size, skin thickness, contact of the crystal, positioning of limb, vasoconstriction can all affect the accuracy. 10
noninvasive monitoring Oscillometric ABP: Systolic, diastolic, MAP, and HR can be determined MAP=(CO x SVR) + CVP MAP=DBP + 1/3(SAP-DBP) =1/3 SAP + 2/3 DBP Cuff size, skin thickness, contact or positioning of cuff in relation to the artery, choice of artery, positioning of limb, vasoconstriction can all affect the accuracy. noninvasive monitoring Pulse oximetry: arterial oxygenation Inaccurate when hypotension and peripheral vasoconstriction ( hypothermia, pain) Normal above 85% noninvasive monitoring Capnometry: determine the partial pressure of exhaled CO2, which is closely related to arterial partial pressure of CO2. Indirectly provide info on cardiac output Exhaled CO2 depends on adequate perfusion of the lungs (delivery of CO2 to lungs) Hypoventilation (increased arterial partial pressure of CO2) can be detected. Normal 30~40 mmhg invasive monitoring Direct ABP measurement Through peripheral artery catheter (dorsal pedal most common) invasive monitoring CVP Monitor right heart function -> intravascular volume Detect early cardiac failure or fluid overload 11
invasive monitoring Arterial and venous BG ABG provides info on ventilation(paco2) and oxygenation(pao2). VBG provides info on tissue perfusion and cardiac output. Fluid therapy 2.5% Dextrose 0.45% NaCl or 0.45% NaCl Rate: Normal healthy non-cardiac patient 10 ml/kg/hr Cardiac patient 2~3 ml/kg/hr and monitor with CVP Aftercare Basic nursing care Maintain BT by warm water bottle, incubator, or other devices Reduce stress and anxiety Aftercare Oxygen therapy By face mask, nasal cannula, or oxygen cage Aftercare ECG monitoring Monitor cardiac rate and rhythm until complete recovery Aftercare Cardiovascular monitoring Post-op invasive or noninvasive ABP or CVP monitoring depending on the severity and stability of the cardiac patient 12
Analgesia Analgesia Preemptive analgesia with premed If necessary, intermittent or continuous analgesia at least 12 to 24 post-op Transdermal Fentanyl 2 delivery size patches: 25 and 50 mcg/hr < 3 kg: ½ of 25 patch 3~10 kg: 25 10~20 kg: 50 20~30 kg: 75 ( 25+50) >30 kg: 100 (50+50) Applied 12~24 hr prior to Sx in dogs, 8~12 hr in cats Analgesia Morphine(0.12 mg/kg/hr) or fentanyl(2~10 mcg/kg/hr) can be used alone to provide post-op analgesia. Analgesia Opioid combinations dogs Morphine-lidocaine-ketamine Preparation: 1 L of 0.45% NaCl or 2.5%Dextrose/0.45% NaCl 1.8 ml of Morphine(15 mg/ml) 15 ml of lidocaine(2%, 20mg/ml) 0.6 ml of ketamine(100 mg/ml) May require 10 ml/kg/hr during Sx. Can be as slow as 2.5 ml/kg/hr 2.5 ml/kg/hr post-op Analgesia Opioid combination dogs Fentanyl-lidocaine-ketamine Preparation: 1 L of 0.45% NaCl or 2.5%Dextrose/0.45%NaCl 15 ml of lidocaine(2%; 20 mg/ml) 0.6 ml of ketamine(100 mg/ml) 24 ml of fentanyl(50 mcg/ml) 2.5 ml/kg/hr Analgesia Opioid combinations cats Cats cannot tolerate lidocaine Excited or dysphoric after opioids. Use tranquilizer ( eg. Acepromazine 0.025 mg/kg IV) to decrease the opioid dose 13
Analgesia Opioid combinations cats Morphine-ketamine Preparation: 1 L of 0.45% NaCl or 2.5%Dextrose/0.45% NaCl 1.8 ml of Morphine(15 mg/ml) 0.6 ml of ketamine(100 mg/ml) May require 10 ml/kg/hr during Sx.. Can be as slow as 2.5 ml/kg/hr 2.5 ml/kg/hr post-op Analgesia Opioid combinations cats Fentanyl-ketamine Preparation: 1 L of 0.45% NaCl or 2.5%Dextrose/0.45%NaCl 0.6 ml of ketamine(100 mg/ml) 24 ml of fentanyl(50 mcg/ml) 2.5 ml/kg/hr Anesthetic considerations for specific cardiac diseases and recommended anesthetic protocols Common cardiac diseases and anesthesia techniques for dogs Mitral valve insufficiency >>mild arterial vasodilation from anesthetic drugs can reduce the regurgitant fraction across MV and maximize cardiac output >>SV and V arrhythmia is common Anesthetic considerations for specific cardiac diseases and recommended anesthetic protocols Common cardiac diseases and anesthesia techniques for dogs Dilated cardiomyopathy >>Inotropic support with dobutamine is recommended for any major surgical procedure regardless of ASA classification >>Mild arterial vasodilation can maximize cardiac output >>Tachycardia may predispose to ventricular arrhythmia. Atropine or glycopyrrolate is not recommended Anesthetic considerations for specific cardiac diseases and recommended anesthetic protocols Common cardiac diseases and anesthesia techniques for dogs Congenital defects AS and PS >>Cardiac output is highly dependant on HR. Inotropic support little or none. Bradycardia should be avoided. >>atropine or glycopyrrolate only if necessary with half the dose. Anesthetic considerations for specific cardiac diseases and recommended anesthetic protocols Common cardiac diseases and anesthesia techniques for dogs Congenital defects PDA and VSD >> pulmonary overcirculation results in a rapid uptake of inhalation anesthetics -> more rapid induction >> may be a delay in distribution of IV anesthetics >> mild arterial vasodilation may reduce the amount of shunt. 14
ASA II patients: medical procedure or minor, minimally invasive surgical procedures Injectables Premed with neuroleptanalgesic combination of acepromazine (0.025 mg/kg IM) and butorphanol (0.4 mg/kg IM). Induction with ketamine(100mg/ml)- diazepam(5mg/ml) ( 0.1 ml/kg of 50:50 mixture) Maintain with intermittent bolus of 1/3 to ¼ dose. Monitor physical parameters, ECG, Doppler ABP, Pulse Ox, EtCO2 ASA II patients: medical procedure or minor, minimally invasive surgical procedures Injectables Premed with neuroleptanalgesic combination of acepromazine (0.025 mg/kg IM) and butorphanol (0.4 mg/kg IM). Induction with propofol (2-6 mg/kg IV) Maintain with CRI (0.14~0.4 mg/kg/min) or intermittent bolus of 0.5~1 mg/kg IV. Monitor physical parameters, ECG, Doppler ABP, Pulse Ox, EtCO2 ASA II patients: medical procedure or minor, minimally invasive surgical procedures Inhalation anesthetics Premed with neuroleptanalgesic combination of acepromazine (0.025 mg/kg IM) and butorphanol (0.4 mg/kg IM). Potent opioid usually not required. Induction with ketamine(100mg/ml)- diazepam(5mg/ml) ( 0.1 ml/kg of 50:50 mixture) KV is preferred over propofol to produce longer duration hence less inhalation. Maintain with lowest possible of isoflurane or sevoflurane. Monitor physical parameters, ECG, Doppler ABP, Pulse Ox, EtCO2 ASA II: Major surgery Inhalation anesthetics Premed with Acepromazine(0.025 mg/kg IM) and hydromorphone(0.2 mg/kg IM). Induction with ketamine(100mg/ml)-diazepam(5mg/ml) ( 0.1 ml/kg of 50:50 mixture) KV is preferred over propofol to produce longer duration hence less inhalation. Maintain with lowest possible dose of isoflurane or sevoflurane CRI of fentanyl-lidocaine-ketamine with the anesthetic rate of fluid 2.5~10ml/kg/hr at the beginning of surgery. Intermittent bolus of opioid agonists may be necessary during Sx. NMRDs may be used with ventilation if BP is low and not well anesthetized. Pancuronium (0.02~0.04 mg/kg IV) has a longer duration of action than atracurium(0.25 mg/kg IV) ASA III or IV patients: medical pocedure or minor, minimally invasive surgical procedures Injectables Premed with neuroleptanalgesic combination of diazepam (0.4 mg/kg IM) and butorphanol (0.4 mg/kg IM). Induction with ketamine(100mg/ml)- diazepam(5mg/ml) ( 0.1 ml/kg of 50:50 mixture) Maintain with intermittent bolus of 1/3 to ¼ dose. Monitor physical parameters, ECG, Doppler ABP, Pulse Ox, EtCO2 ASA III or IV patients: medical pocedure or minor, minimally invasive surgical procedures Injectables Premed with neuroleptanalgesic combination of diazepam (0.4 mg/kg IM) and butorphanol (0.4 mg/kg IM). Induction with propofol (2-6 mg/kg IV) Maintain with propofol CRI (0.14~0.4 mg/kg/min) or intermittent bolus of 0.5~1 mg/kg IV. Monitor physical parameters, ECG, Doppler ABP, Pulse Ox, EtCO2 15
ASA III or IV patients: medical pocedure or minor, minimally invasive surgical procedures Injectables ASA III or IV patients: medical pocedure or minor, minimally invasive surgical procedures Mainly inhalation anesthetics are NOT recommended for ASA III or IV patients Etomidate(1~2 mg/kg IV) should be used as induction if cardiac arrhythmias are present ASA III or IV patients: Major Surgery Premed with neuroleptanalgesic combination of diazepam(0.2 mg/kg IV) and fentanyl (1 mcg/kg IV). Atropine may be needed if bradycardia Induction with fentanyl (5~10 mcg/kg IV)(slow induction. It may take 30 to 60 second to effect) Or induction with etomidate (1~2 mg/kg IV) if arrhythmias exist. Maintain with fentanyl 5~10 mcg/kg /hr CRI Ventilation all time NMRDs may be used with ventilation if BP is low and not well anesthetized. Pancuronium (0.02~0.04 mg/kg IV) has a longer duration of action than atracurium(0.25 mg/kg IV) Direct BP, ECG, EtCO2, Pulse Oxymetry, and physical parameters are routinely monitored. Canine pericardiocentesis ASA II Not showing signs of pericardial tamponade may only need local infiltration of lidocaine in the skin and intercostal musculature at the site of needle puncture for pericardiocentesis. Sedation for non-compliant patients: neuroleptanalgesic combination of diazepam(0.2 mg/kg IV) and hydromorphone(0.2 mg/kg IV). Atropine only if bradycardia. Canine pericardiocentesis ASA IV emergency pericardiocentesis may only need local infiltration of lidocaine in the skin and intercostal musculature at the site of needle puncture for pericardiocentesis. Sedation for non-compliant patients: neuroleptanalgesic combination of diazepam(0.2 mg/kg IV) and butorphanol(0.2 mg/kg IV). butorphanol is least likely to decrease HR. Occasionally induction is required with etomidate(1~2mg/kg IV) Common cardiac diseases and anesthesia tech for cats HCM ASA II: medical procedure or minor minimally invasive surgical procedures Injectables technique Premed with Acepromazine(0.025 mg/kg IM) and hydromorphone(0.2 mg/kg IM). Propofol(1~3 mg/kg IV) 10~15 min after neuroleptanalgesics Ventilation is required. Propofol(0.14~0.4 mg/kg/min CRI or 0.5 mg/kg IV bolus) may be used for longer procedure. Monitor physical parameters, ECG, Doppler ABP, Pulse Ox, EtCO2 16
Common cardiac diseases and anesthesia tech for cats Common cardiac diseases and anesthesia tech for cats HCM ASA II: medical procedure or minor minimally invasive surgical procedures Inhalation techniques Premed with Acepromazine(0.025 mg/kg IM) and hydromorphone(0.2 mg/kg IM). Propofol(1~3 mg/kg IV) 10~15 min after neuroleptanalgesics Ventilation is required Isoflurane or sevoflurane in oxygen at the lowest effective dosage. ASA II: Major Surgery Inhalation techniques Premed with Acepromazine(0.025 mg/kg IM) and hydromorphone(0.2 mg/kg IM). Induction with Propofol(1~2 mg/kg IV) 10~15 min after neuroleptanalgesics for intubation. Ventilation is required. NMRDs may be used with ventilation if BP is low and not well anesthetized. Pancuronium (0.02~0.04 mg/kg IV) has a longer duration of action than atracurium(0.25 mg/kg IV) Common cardiac diseases and anesthesia tech for cats ASA III or IV: medical procedure or minor minimally invasive surgical procedures Injectables technique Premed with neuroleptanalgesic combination of diazepam(0.2 mg/kg IV) and hydromorphone (0.2mg/kg IV). Induction with nothing or propofol(2~4 mg/kg IV) Or induction with etomidate (1~2 mg/kg IV) if arrhythmias exist. Maintain with propofol CRI (0.14~0.4 mg/kg/min) or intermittent bolus of 0.5~1 mg/kg IV. Endotracheal intubation with oxygenation may be necessary. Monitor physical parameters, ECG, Doppler ABP, Pulse Ox, EtCO2 Common cardiac diseases and anesthesia tech for cats ASA III or IV: Major Surgery Premed with neuroleptanalgesic combination of diazepam(0.2 mg/kg IM) and Hydromorphone(0.2 mg/kg IM). Induction with propofol (2~4 mg/kg IV) 10~15 min after neuroleptanalgesics Or induction with etomidate (1~2 mg/kg IV) if arrhythmias exist. Maintain with fentanyl 3~5 mcg/kg /hr CRI Ventilation all time NMRDs may be used with ventilation if BP is low and not well anesthetized. Pancuronium (0.02~0.04 mg/kg IV) has a longer duration of action than atracurium(0.25 mg/kg IV) Direct BP, ECG, EtCO2, Pulse Oxymetry, and physical parameters are routinely monitored. NO BEST DRUGS NO BEST PROTOCOL Thank you for your attention ONLY BEST DOCTORS, LIKE YOU 17